256 



NA TURE 



[July 16, 1896 



mens in botany, which formed the types incUided in his " Flora 

 of Vucalan," and considerable material for exchange to augment 

 the small herbarium in his department. He also secured about 

 four hundred specimens in zoology, principally conchology, and 

 a number of excellent negatives relating to geology, botany, 

 ethnology and travel. Prof. Holmes secured altogether about 

 one thousand specimens in archa;ology from N'ucatan, Chiapas, 

 Oaxaca, Vera Cruz and the valley of Mexico, and made a 

 number of important observations. An expedition to San 

 Domingo, conducted by Mr. Geo. K. Cherrie, Assistant Curator 

 in the Department of Ornithology, resulted in the collection of 

 195S bird skins, i6 mammals, So reptiles, and a number of 

 specimens of fish and Crustacea. Among the birds, two species 

 proved new to science, and a number of others are very interest- 

 ing as representing rare and little-known forms. Captain Miner 

 \V. Bruce was fitted out by the Museum for an expedition to 

 Alaska and Siberia in June 1894, and he acquired valuable 

 ethnological material from North Alaska. A number of minor 

 expeditions were also organised in the interests of the Museum, 

 and they have resulted in numerous additions to the collections 

 in different departments, as well as the acquisition of information 

 of great scientific value, which information is made known 

 through the admirable series of publications issued by the 

 .Museum. 



The additions to the Zoological Society's Gardens during the 

 jjast week include a Lesser White-nosed Monkey (Cercopilheciis 

 petaurisla) from West Africa, a White-throated Monitor 

 ( Varamis albogularis] from South Africa, presented by Sir Gilbert 

 Carter ; a Vervet Monkey ( Cercopitheciis lalandii) from South 

 Africa, presented by Mr. Henry Russell ; a Diana Monkey 

 (Ccrcopitlictus diaiia) from West Africa, presented by Mr. E. 

 Kirby ; a Striped Hynena (Hyiviia striata) froin Arabia, pre- 

 sented by Mr. C. A. Osborne; a Hamster (Criieliis fnimen- 

 tariiis), European, presented by Miss Hilton ; three Yellow- 

 bellied Liothrix (Liothrix liiteiis) from India, presented by Mr. 

 Robert E. Graves; an Iceland Falcon [Hierofako islandiis) 

 from Iceland, eight Horsfield's Tortoises [Homopus horsfieldi) 

 from Central Asia, two Giant Toads \Biifo iiiarinus) from 

 Brazil, a Reticulated Python {Python r«r//(";(/a/(2) from Malacca, 

 deposited ; two Lettered Aracari {Pteroglosstis inscriptiis) from 

 Para, a Black-necked Swan (Cygniis nigricollis) from Antarctic 

 America, purchased ; a Burrhel Wild Sheep (Oz« /5;«-/-/«/), two 

 Glossy Jbisis (Plegariis fakinelliis), bred in the Gardens. 



OUR ASTRONOMICAL COLUMN. 

 The Cluster in Coma Berenices.— The results of a 

 tri.angulation of the more conspicuous stars in this group have 

 been recently issued from the astronomical observatory of Yale 

 College. This contribution to a class of observations that is 

 now receiving much attention, has been made with the helio- 

 meter by Mr. F. L. Chase at the suggestion of Dr. Elkin. The 

 instrument employed is the same that Dr. Elkin used in his 

 measurements of the Pleiades group, and the method of reduc- 

 tion follows generally the same lines that were then adopted ; 

 but the different configuration of the fundamental stars on which 

 the measures are based, has enabled the observer to dispense in 

 some degree with measures of position angle, the less trust- 

 worthy coordinate in heliometer observations, and to rely upon 

 measures of distance from six selected stars, five of which form 

 nearly an equilateral pentagon, the sixth being approximately 

 in the centre. Two lines of stars roughly crossing the pentagon 

 at right angles, and extending some six degrees, have been 

 utilised for determining the scale value. The final result is to 

 give the coordinates of thirty-three stars (Equinox 1892 'O) limited 

 to about the 8'5 mag., below which magnitude the most satis- 

 factory observations cannot be made with the Yale instrument. 

 An examination of the probable errors of the measures, classified 

 according to the magnitude of the stars, does not disclose any 

 law dependent on brightness, so that .Mr. Chase has not over- 



NO. 1394, VOL. 54J 



stepped prudence in this respect. At the same time the posilimi 

 of so many well-scattered points of reference has been deter- 

 mined, that it should be an easy task, and one worthy nl 

 accompli.shinent, to derive the places of the remaining and 

 fainter stars of the group by means of photography. 



Objeciive Gratincs.— Messrs. Hall and Wadsworth de- 

 scribe in the June number of the Aslrophysical Journal the 

 results of a fairly successful application of an objective grating, 

 constructed on the original Fraunhofer method, and attached 

 to a 12-inch photographic object-gl.ass, whose ratio of aperture 

 to its focal length is as 1: 18. Two screws 27 cm. long, and 

 with 63 threads to the centimetre, weie cut in two along their 

 axes, and the half-screws mounted, parallel to each other, on 

 the opposite sides of rectangular frames. Copper wire was 

 wound across in the successive threads, and soldered to the 

 screws so as to produce a grating. When applied to the tele- 

 scope, photographic spectra of both the first and second order 

 could be obtained, and cases are ([uoted showing the agreement 

 of the deduced wave-length with Rowland's values. One of 

 the difficulties experienced in the u.se of this form of grating 

 arises from the wind disturbing the lines of the grating, an 

 annoyance which, it is suggested, might be prevented by solder- 

 ing light rods across the wires parallel to the half-screws. The 

 time required for exposure with objective gratings is of course 

 longer than with the objective prism : but against these twt> 

 disadvantages is to be set the comparative small cost of con- 

 struction. In the one used in the expermients at Chicago, the 

 cost was only one-thirtieth of that of an equally large objective 

 prism of small angle, and evidently the advantage on the side 

 of economy increases as the aperture increases. In the case 

 of the Yerkes telescope, it is computed that the grating would 

 cost about the two-hundredth part of the prism of the same 

 size. 



Distortion ok the Earth's Surface. — Under the title of 

 " .\n Earth-bending Experiment," Prof. H. H. Turner gives a 

 description of a series of observations undertaken at Oxford by 

 Prof. J. Milne {Obse7~i'atoyy, Tuly'i. In his investigation of 

 terrestrial disturbances in the Isle of Wight, Prof. Milne found 

 evidence of their being due to several causes. For instance, 

 some are due to real local earthquakes on a small scale, some 

 owing to faint echoes of very distant earthquakes, while it 

 appears that others may have their origin in the various states 

 produced on the surface of the ground by meteorological causes. 

 These last have specially attracted attention, as it is quite 

 possible that the considerable load represented by a shower of 

 rain or snow, or a heavy fall of de«', may be capable of bending 

 the surface of the ground to such a degree as to affect the 

 stability of any astronomical instruments not having very deep 

 foundations. In looking for these eftects, it might be expected 

 that tilts due to rainfall, though irregular, would show some 

 evidence of an aH«;;a/ periodicity, while those produced by dew 

 would show a i/««-«a/ variation. To test whether any of these 

 causes might have an appreciable disturbing effect, the 

 University Observatory at Oxford was chosen as being 

 particularly suitable, standing alone in a grassy park. The 

 instruments for detecting and recording any difference of level con- 

 sisted of one of Prof. Milne's horizontal pendulums and the level 

 of the Barclay transit circle. The effect of a sudden shower was 

 imitated by securing the services of seventy-six people, who were 

 marched, in various degrees of compactness, up to and away 

 from the slate slab supporting the registering apparatus. The 

 result of these experiments was that a small depression was 

 observed, always towards the crowd, the maximum value, how- 

 ever, being only o"'5, when the load was concentrated and close 

 to the instrument. The load employed being estimated greater 

 than is likely ever to be produced by rain, &c. , it is concluded 

 that on that particular site at least no disturbance due to 

 meteorological causes need be feared. 



ON THE LIQUATION OF CERTAIN ALLOYS 

 OF GOLD} 



'PHE molecular distribution of the metal in alloys of gold 



and of metals of the platinum group has been described 



by me in several papers, the most important of which has 



been published in the Philosophical Transactions. New 



1 .\l)ridged from .-i paper rcid l)efore die Roy.al Society, M.-iy 7. 



